A control method and a control device for controlling a spark-ignition internal combustion engine that is equipped with a turbocharger and an exhaust gas recirculation device. The operation of the engine is carried out to perform a stoichiometric air-fuel ratio by performing exhaust gas recirculation even in a high-load range including a maximum-output operation point. When the maximum output operation point is required, intake air information such as atmospheric pressure and outside air temperature is used as a basis to calculate intake air density, which is compared with a predetermined density threshold. When the intake density is equal to or less than the density threshold at a high-altitude location or the like, an exhaust gas recirculation rate is set to 0. As a result, the maximum output can be higher than when exhaust gas recirculation is performed.

It is an object to suppress turbo lag, while suppressing a decrease in torque in an acceleration-transient state to a supercharged state, occurring owing to a rise in required load. In a prescribed steady state, an engine compression ratio m and ignition timing Tm are set so as to achieve a maximum thermal efficiency. In contrast, in a transient state from a non-supercharged state to a supercharged state, occurring owing to a rise in required load, the engine compression ratio is corrected to a higher compression ratio h and concurrently the ignition timing is corrected to a retarded timing value Th, in comparison with the engine compression ratio m and the ignition timing Tm during steady-state operation for the same load, thereby increasing exhaust energy due to a reduction in cooling loss and consequently suppressing a delay of response to a rise in supercharging pressure.

A turbocharged internal combustion engine is provided with at least a partially variable valve train on an intake side wherein the intake valves are controlled to optimize the actuation of a second inlet valve in relation to a first inlet valve for different load conditions.

Embodiments for operating an engine with skip fire are provided. In one example, a method comprises during a skip fire mode or during a skip fire mode transition, port injecting a first fuel quantity to a cylinder of an engine, the first fuel quantity based on a first, predicted air charge amount for the cylinder and lean of a desired air-fuel ratio, and direct injecting a second fuel quantity to the cylinder, the second fuel quantity based on the first fuel quantity and a second, calculated air charge amount for the cylinder.

Systems and methods for detecting and controlling knock in an engine are presented. In one example, engine knock sensors are selected based on whether or not certain cylinders are activated and combusting air and fuel or deactivated and not combusting air and fuel. Output of selected knock sensors is the basis for adjusting engine spark timing.

A control method and a control device for controlling a spark-ignition internal combustion engine that is equipped with a turbocharger and an exhaust gas recirculation device. The operation of the engine is carried out to perform a stoichiometric air-fuel ratio by performing exhaust gas recirculation even in a high-load range including a maximum-output operation point. When the maximum output operation point is required, intake air information such as atmospheric pressure and outside air temperature is used as a basis to calculate intake air density, which is compared with a predetermined density threshold. When the intake density is equal to or less than the density threshold at a high-altitude location or the like, an exhaust gas recirculation rate is set to 0. As a result, the maximum output can be higher than when exhaust gas recirculation is performed.

Various systems and methods are described for controlling pre-ignition in a boosted engine in a newly manufactured vehicle. One method comprises, during a pre-delivery phase of the vehicle, operating the boosted engine in a pre-delivery calibration with a first, higher enrichment, in response to a pre-ignition event. The pre-delivery calibration is deactivated during a post-delivery phase and the boosted engine is operated with a second, lower enrichment in response to a pre-ignition event.

Methods and systems are provided for indicating degradation of a VCR mechanism that mechanically alters a cylinder compression ratio. Degradation is detected based on an elevated knock incidence and increased spark retard usage. If the VCR mechanism is stuck, knock and pre-ignition that could be induced by continued operation in a higher than intended compression ratio is mitigated by limiting the engine load.

An internal combustion engine includes an intercooler configured to cool an intake gas compressed by a compressor, a cooler bypass passage configured to bypass the intercooler, and a cooler bypass valve configured to open and close the cooler bypass passage, and an exhaust gas recirculation gas is introduced into an upstream side of the intercooler. An electronic control unit is configured to open the cooler bypass valve during use of a high exhaust gas recirculation rate region, and to close the cooler bypass valve during use of a low exhaust gas recirculation rate region.

There are provided a control device and an abnormal combustion detecting method for detecting occurrence of abnormal combustion during an expansion stroke of an internal combustion engine. The control device of the present invention receives a detection signal of a vibration sensor for detecting pressure vibration in a combustion chamber, and detects occurrence of knocking based on a knocking-specific frequency component extracted from the detection signal in a knocking determination region within the expansion stroke. In addition, the control device detects the characteristic value, different from the knocking-specific frequency component, of the detection signal in an abnormal combustion determination region which includes the knocking determination region and which expands over the compression stroke before ignition timing and the expansion stroke, and detects self-ignition during the compression stroke before ignition timing and self-ignition during the expansion stroke, based on the characteristic value.